A number of plant diseases caused by pathogens such as fungi, moulds, oomycetes, bacteria and viruses are known. Many of them, usually connected with climatic conditions favouring their onset and diffusion, have dramatic consequences, causing losses of yields of crops which may have a deep and sometimes catastrophic impact on agricultural economy, especially when the disease assumes the epidemic status.
An historically remarkable example of a plant disease causing devastating consequences is the potato infection (late blight) by Phytophthora infestans responsible for the great Irish famine of in the late 1840s.
Another oomycete, Plasmopara viticola, is responsible for the so called downy mildew, one of the most widespread infections affecting, causing huge damages to wine producers and grape growers, negatively affecting the yield as well as the quality of production.
A similar grapevine disease, called powdery mildew, is caused by the fungus Erysiphe necator, also known as Uncinula necator. 
Similar infections affect other plants such as soybean, sunflower, lettuce, tomato, potato, oaks, ornamental plants, fruit plants, tobacco, cucurbits.
A comprehensive review on plant disease is reported in the European Handbook of Plant Diseases, ed. by I. M. Smith et al., 1988, Blackwell Scientific Publications.
Several natural and synthetic agents have been proposed and are available for treating the above mentioned plant diseases.
In addition to sulfur and copper salts or complexes, synthetic fungicides for agrochemical use belong to very broad and different chemical classes (phenylamides, benzimidazole derivatives, dicarboximides, carbamates, carbanilates, dithiocarbamates, dinitroanilines, etc.). The use of said synthetic agents is limited by the well known phenomenon of resistance as well as by the toxic effects which may be induced by said agents in humans and animals and by their environmental pollution potential.
Research efforts are therefore being paid for developing more environment-friendly fungicides, possibly of natural origin, which may possibly substitute the known synthetic fungicides or at least which may be used in combination with them in order to reduce the resistance phenomenon and/or their environmental impact.
Several oils such as cinnamon essential oil, rosemary oil and neem oil are known as effective fungicides.
U.S. Pat. No. 6,174,920 discloses moreover the use of jojoba wax for controlling powdery mildew infections.
Jojoba extract has also been reported as a pre-treatment to prevent powdery mildew infection on grape plants in CA 2,103,014 whereas US 2007/0071831 discloses a product for the prevention and/or treatment of infections obtained by the partial or total neutralization of lees deriving from winemaking processes.
WO 2006/006878 discloses a fungicidal composition comprising anhydrous fat milk optionally in combination with one or more of soybean oil, olive oil and coconut oil.